This invention relates to a relief thread grinding machine for making screw taps or the like, wherein a workpiece is clamped to a relief grinding body of a longitudinally movable sled and a stroke producing device arranged on the sled provides the grinding body with an oscillating transverse movement while the workpiece rotates and is axially advanced by the sled past a laterally movable grinding disc.
A thread grinding machine for relief grinding the threads of taps and internal thread forming devices is disclosed in German Pat. No. 2,442,384. The tap stock is rotatable parallel to the workpiece spindle and is clamped to an upper part of a workpiece sled. This upper part is elastically connected with the lower part of the sled by leaf springs. A pivot lever attached in a lower part is actively connected with the upper part. The lever engages a rotating cam through a follower roller, and the lobe of the cam imparts an oscillating or swinging motion to the lever. The lever in turn induces oscillating movements of the upper part of the sled relative to the under part thereof as is necessary for relief grinding, whereby the swinging movements occur transverse to the workpiece axis.
The cam is exchangeably mounted to enable myriad forms of relief grinding. Adjustment of the relief grinding stroke is accomplished by means of an adjustable template in the lever which engages a guide roller mounted in the upper part.